A Compact Design Using GaN Semiconductor Devices for a Flying Capacitor Five-Level Inverter

Multilevel inverters (MLIs) based on the flying capacitor (FC) concept are beneficial in many renewable energy-based applications due to their compactness, low current stress on semiconductor devices, and reasonable thermal behavior for high-power applications. However, the recently developed FC-based topologies suffer from half dc-link voltage utilization and a variable high-frequency common-mode voltage (HF-CMV). The aim of this paper is to propose an FC-based family of MLIs with a five-level (5L) output voltage, full dc-link voltage utilization, and low HF-CMV. Using redundant states and the phase-shifted sinusoidal PWM technique, the value of the flying capacitor has been reduced significantly. The performance of the converter has been verified using Gallium Nitride (GaN) power switches. Circuit description and a brief comparative study with existing MLIs are given to justify the suitability of the topology.